Fuel injection system and apparatus



May 14, 1963 G. c. GRAHAM FUEL INJECTION SYSTEM AND APPARATUS 4 Sheets-Sheet 1 Filed 001'.. 9. 1959 l Tll..

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/25 /33 Ebb-75 May 14, 1963 G. c. GRAHAM FUEL INJECTION SYSTEM AND APPARATUS 4 Sheets-Sheet 2 Filed Oct. 9. 1959 AT ONEY May 14, 1963 G. c. GRAHAM 3,089,422

FUEL INJECTION sYsTEN AND APPARATUS Filed Oct. 9. 1959 4 Sheets-Sheet 3 Tlrzlz. /52 T1 .7. /35 /25/26 :I 77

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ATTORNEY May 14, 1963 G. c. GRAHAM FUEL INJECTION SYSTEM AND APPARATUS INVENT 'Filed 0G13. 9. 1959 United States Patent O 3,089,422 FUEL INJECTION SYSTEIVI AND APPARATUS George C. Graham, 76 Crest Road, Ridgewood, NJ. Filed Oct. 9, 1959, Ser. No. 845,410 13 Claims. (Cl. 10S-38) This invention relates to liquid distributing systems, and more particularly to a fuel pumping system and apparatus adapted to distribute separate and equal amounts of fuel to corresponding fuel injection nozzles of an automotive engine or the like.

An object of the invention is to provide a fuel injection system and apparatus for internal combustion engines and the like whereby fuel is eiectively distributed in accurately metered quantities to the separate cylinders of the engine.

Another object of the invention is the provision in a fuel injection system of `a distributing pump which has substantially reduced mating and sliding surfaces of moving parts compared to those of prior art pumps, whereby operating friction of the apparatus is reduced to an extreme minimum. This is manifest in that the small pistons in the present apparatus each have an engine idling stroke in the order of 3 or 4 thousandths of an inch while at maximum throttle for vehicle running speed of about 100 miles per hour, the piston strokes range up to the order of approximately 35 thousandths of an inch. The substantially friction-free characteristic of the apparatus is implicit in its requirement of only about electrical watts or of about 1/30 horsepower for its operation as compared with requirements of up to the order of 1/2 horsepower for other pumps made for the same purpose. Due to this Very low friction there is no appreciable heating of the pump during its operation.

A salient feature of the present invention is the provision of so-called free pistons in the distributing portion of the system which are given intermittent power strokes in succession by an adjustable cam rotating on a shaft, said pistons being returned to their starting position by a hydraulic head maintained by a fuel supply pump operating in conjunction with fuel injection nozzles which also act automatically as check valves for the hydraulic systems of the respective cylinders in which said pistons operate.

Another feature of the invention is the provision of ta simple camming mechanism for variably controlling the length of piston stroke in the distributing portion of the apparatus whereby desired quantities of fuel will be transmitted through the corresponding injection nozzles for controlling the speed and power of the automotive engine.

The apparatus of the present invention is readily manufactured by comparatively inexpensive means and without highly critical tolerances, its parts are readily replaceable, it is simple to maintain and service and can be made at low cost of suitable materials such as steel, plastics, or the like, and can be sold for an amount in the same order as the cost of an equivalent carburetor system, or possibly less.

Still other objects and advantages of my invention will be apparent from the specification.

The features of novelty which I believe to be characteristic of my invention are set forth herein and will best be understood, both as to their fundamental principles and as to their particular embodiments, by reference to the specification and accompanying drawings, in which:

FIGURE l is a side elevation of the fuel distributing pump of the present invention;

FIG. 2 is a view taken on line 2 2 of the pump shown in FIG. l, some parts being omitted;

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FIG. 3 is principally an enlarged section view taken on line 3 3 of FIG. 2, some parts being in elevation and other parts being in phantom outline; showing addition- `ally in a somewhat enlarged side view, partly in section, a combination injector nozzle `and check Valve connected to one of the distributor tubes of the distributing pump, and showing further, in schematic representation, a liquid supply source and a supply pump connected to the distributing pump;

FIG. 4 is a view taken on line 4 4 of FIG. 3, some parts being shown in section, and other parts being broken away;

FIG. 5 is a view taken on line 5 5 of F-IG. 3, some parts being shown in phantom outline, and some parts omitted;

FIG. 6 is a greatly enlarged portion of FIG. 3, some parts being shown in section, some in elevation, and others in phantom outline;

FIG. 7 is a greatly enlarged fragmentary view of the inlet valve portion of the pump taken on line 7 7 of FIG. 9;

FIG. 8 is a greatly enlarged fragmentary view of the same portion of the pump taken on line 8 8 of FIG. 9;

FIG. 9 is a section view ltaken on line 9 9 of FIG. 7;

FIG. 10 is an enlarged perspective view of one of the elements of the inlet valve shown in FIGS. 7 and 9;

FIG. 1l is a perspective view of the control rod and cam control element of the pump;

FIG. l2 is an extremely enlarged fragmentary section view taken on line 12-12 of FIG. 6, some parts being shown in phantom outline and some parts being shown in elevation, and showing various positions of one of the control elements;

FIG. 13 is a greatly enlarged illustration of an alternative embodiment of the piston return means;

FIG. 14 is a greatly enlarged view of the inlet fitting of the pump; and

FIG. 15 is a greatly enlarged section view of an alternative embodiment for the inlet valve shown in FIG. 7.

Referring to .the drawings in detail, the distributor pump of the present invention comprises la circular cylinder housing 2.1 having an outer wall 22, and an inner wall 23 (FIGS. l and 4). Joined to cylinder yhousing 21 and having substantially the same diameter is a circular inlet housing 24 with `an outer wall 25 and an inner wall 26 (FIG. 5), the latter wall being in `abutment with inner wall 23. Cylinder housing 21 and inlet housing 24 are secured to each other by means of threaded bolts 217 (FIGS. 4, 5, 1 6) symmetrically disposed in circular arnay around the axial centers of, and `extending through suitable apertures in, said housings.

Cylinder housing 21 has a ycentral circular aperture 321 (FIGS. 3 and 6) Iwhich `accommodates the stationary outer race of ball bearing 32 `while inlet housing 24 has a central `circular aperture 33 which accommodates the stationary outer nace of @ball bearing 34. Drive shaft 35 extends through and is connected Ifast to the rotatable inner races (not shown) of both of said ball bearings.

'Ihe end of drive shaft 35 extending outwardly from the inlet housing has Va flat 36 with which 'a drive coupling 37 mates, said coupling being connected to a suitable rnotive for-ce, such as an electric motor `or through suitable gearing to an 'automotive engine or the like. 'Iihe peripheral sunface of bearing 34 has an .annular groove which `accommodates an outwardly extending ring 3S whose peripheral edges are seated against the shoulder of -circular recess 39 in the central `aperture 33 of inlet housing Z4. Also positioned within recess 39 is a circular spring 41 maintained therein by circular retainer plate 42 seated in la recess 43 in the outer face of inlet housing 24. Retainer plate 42 is secured to linlet housing 24 by rneans of screws 44 (FIG. 6). Plate 42 has a 3 central aperture 45 through which shaft 35 extends and rotates freely. Shaft 35 extends through and rotates within a central chamber 46 within cylinder housing 21. `Connected by means of suitable screws, not shown, to boss 52 on housing 21 is the circular liange 53 of journal 54. The axial bore 55 of journal 54 accommodates a longitudinally slidable `control rod 56, the surface of which may be scored or otherwise marked with a plurality of spaced apart lines 57 for calibration purposes as will be explained hereinbelow.

The inner end of rod 56 has a longitudinal laxial recess S which accommodates one end of elongated cam control element 5-9. Cam control element 59 is required to rotate around its longitudinal axis while control rod 56 is capable only of longitudinal motion; therefore, control element 59 is provided with an annular recess 61 into which dog 62- of set screw 63 extends, the latter being threadably inserted radially in rod 56. Annular recess 61 is slightly wider than the diameter of dog 62 whereby control element 59 is permitted to rotate freely relative to non-rotating control rod 56. The longitudinal movement of control rod 56 imparts rectilinear motion to control elernent 59 =within bore 55 of journal 54 as well as within axial bore 65 of shaft 35. The surface of control element 59 has a longitudinal keyway 66 which slidably engages key 67 which extends partilaly into -bore 65 of shaft 35 (FIGS. 3 and 4). Key 67 constitutes the inner end of screw 68 threadably secured in a suitable radial aperture in shaft 35; thus the rotation of shaft 35 causes the rotation of control element 59 therewith. Cam -control element 59 has a sloping camming surface 69 of low pitch whose function will be described more fully hereinbelow (FIGS. 3 and 6).

Inlet housing 24 has a radially disposed inlet aperture 71 which threadably accommodates a cylindrical inlet titting 72 secured therein with a suitable liquid-tight seal (FIGS. 3, 6 and 14). Inlet tting 72 has an outwardly extending threaded extension 73 to which one end of a suitable feed tube may be connected, the other end of said tube being in turn connected to a suitable source of liquid such as gasoline fuel, or the like. The inner end of aperture 71 communicates 'with circular inlet groove 74 cut in the inner face 26 of said housing (FIGS. 3, 5, 6, 7). The inner 4face 23 of cylinder housing 21 has a pair of concentric spaced apart circular recesses 75 and 76 which accommodate resilient O-rings 77 and 78, respectively, that `are maintained -under pressure between inlet housing 241and cylinder housing 21.

It will 4be noted that O-rings 77 and 78, which are made of rubber or the like, 'are of greater and lesser diameter, respectively, than the diameter of inlet groove 74 whereby an effective liquid-tight seal is provided to prevent escape of fuel either inwardly or outwardly in respect of the pump assembly. O-rings 77 and 78 also effectively seal olf inlet groove 74 to ensure proper fuel flow into the inlet valves described hereinbelow.

Spaced uniformly apart in a circle in face 23 of cyinder housing 21 yare a plurality of circular inlet valve recesses 81 in which -are seated respective inlet valve -assemblies (FIGS. 3, 4, 7 Said inlet valve assemblies serve respective cylinders 82 that are arrayed radially in one plane around shaft 35 in cylinder housing 21. When the pump is arranged to serve an eight cylinder engine, eight pump cylinders 82 (FIG. 12) as well as eight inlet valve assemblies therefor (FIG. 4) yare provided.

Each inlet valve assembly comprises a backing washer 85 whose central aperture 86 accommodates one end of locating pin 87, the other end of which rests in a suitable recess 83 in the body of cylinder housing 21 (FIG. 7). Abutting the inner surface of lbacking washer 85 is a ring shaped U-cup 91 made of a suitable resilient material such as rubber, or the like, which acts as a unidirectional valve. U-cup 91 is maintained against backing washer 85 by one end of a circular support collar 92 positioned in the circular valley of said cup, the other end of said col- 4 lar abutting the inner face of recess 81 (FIGS. 7, 9, 10).

The outer periphery of the widest portion of backing washer is slightly spaced apart from the interior walls of aperture 81 whereby liquids can llow therebetween and under pressure beyond the outer resilient flange of U-cup 91. It will be noted that the mouth of recess 81 overlaps a considerable portion of the mouth of inlet groove 74 (FIGS. 3 and 7), whereby fuel llows from the latter to the former around a narrowed stem of washer 85 and llows past the outer flange of U-cup )1.V The internal diameter of washer 85 may be slightly greater than the external diameter of pin 87 whereby fuel may also flow therebetween and past the inner flange of U-cup 91 into the space within the interior of collar 92. The inner end of collar 92 has a pair of notches 93 disposed oppo site each other, said notches permitting fuel to llow from the interior of said collar to the exterior thereof and thence through a communicating port 95 (FIGS. 7, 8, 9 and 10) to its corresponding cylinder 82.

As is observed from FIGS. 7, 8 and 9, valve apertures 81 are offset radially from their respective cooperating cylinders 82. Should greater fuel pressure be exerted within a cylinder 82 than obtains in inlet groove 74, the respective flanges of U-cup 91 will be caused to be urged against the interior walls of recess 81 and against pin 87 whereby huid is prevented from escaping from the cylinder through port 95.

Each cylinder 82 slidably accommodates an elongated reciprocable piston 101, made of steel, nylon, or other suitable material (FIGS. 3, 4, 6, l2), and provided with an outwardly extending central longitudinal stem 102 around which is positioned circular U-cup 103 made of resilient material such as rubber or the like. U-cup 103, which moves with piston 101, serves as a sliding seal to prevent leakage of liquid inwardly past said piston.

Each of the pistons is actuated outwardly only by a cam assembly that is mounted on shaft 35. In the same plane as the array of cylinders S2, shaft 35 has an annular recess 104 I(FIGS. 3, 6, 12). In that location, one portion of shaft 35 has a somewhat semi-circlar periphery 105 while the remaining portion has a bow-shaped periphery 106 (FIG. l2). This narrowed section of shaft 35 has a radial aperture 107 which slidably accommodates plunger pin 108, the inner end of which bears against cam surface 69 of cam control element 59. The longitudinal position of plunger 108 is determined by the extent to which cam surface 69 of element 59 is moved inwardly or outwardly in respect of the plane in which pistons 101 are arrayed.

Piston 101 is a free piston which is not mechanically or positively connected to any other part of the pump. It moves longitudinally in one direction within its cylinder 82 only by actuation of hydraulic or fluid pressure at one end, and by cam action upon its other end which urges it in the opposite direction for its power stroke. In other words, the action of piston 101 is freely responsive to whatever actuation is applied at either of its ends.

Connected between spaced apart portions of shaft 35 across recess 104 and positioned substantially parallel to the central axis of said shaft is a pin 109 (FIGS. 6, 12), to which rocking cam 111 is pivotally connected. In FIG. 12, rocking cam 111 is shown in three typical positions; as, for example, minimum or zero stroke A, intermediate stroke B, and maximum stroke C, depending upon the position of plunger pin 108 as determined by the action of cam control element 59.

Rocking cam 111 has a forwardly extending tongue 112 which leads its traverse as it moves with rotating shaft 35, as indicated by the arrow in FIG. l2, in respect of stationary cylinder housing 21. Extending rearwardly of pin 109, rocking cam 111 has a leg element 113 against whose heel 114 the outer end of plunger pin 103 bears. As control rod 56 is pushed inwardly or outwardly, the sloping camming surface 69 of control element 59 governs the corresponding outward or inward motion of plunger pin 103 and the consequent rocking action of cam 111.

The tongue portion 112 of rocking cam 111 forward of pin 109 never comes in contact with any of the pistons 101. When shaft 35 rotates, centrifugal force urges tongue 111 of rocking cam 111 outwardly and consequently by pivoting action, causes heel 114 of leg 113 of the cam to be urged inwardly against the outer end of plunger pin 108, and the other end of which bears against camming surface 69 of control element 59. This arrangement obviates the necessity for any spring element, or the like, to control plunger 108.

As control element 59 is moved inwardly into the bore 65 of shaft 35, sloping camming surface 69 on said element urges pin 103 outwardly to lift leg 113 of cam 111, thereby moving its outer camming surface 115 a greater radial distance from the axial center of shaft 35. The degree to which camming surface 115 is positioned relative to said axial center determines the extent to which camming surface 115 will work against the inner ends of pistons 101 which are equidistantly spaced from said axial center. Thus, the greater the angular displacement of camming surface 115 from the axial center of shaft 35, the greater the magnitude of pressure strokes that are produced by pistons 101 as the latter are urged outwardly by said cam surface 115.

Concomitantly, the outward movement of control element 59 from bore 65 of shaft 35 permits the inward movement of camming surface 115 toward the axial center of shaft 35. This action is effected by the rotation of shaft 35 producing centrifugal force by which tongue 112 causes cam 111 to rotate on pin 109. The closer camming surface 115 is to the axial center of shaft 35, the shorter the pressure strokes that will be produced by pistons 101.

By means of the foregoing arrangement, the pressure strokes of pistons 101 are variably controlled depending upon the extent lto which control rod 56 is moved reciprocably within journal 54. The desired -setting of camming surface 115 may be determined either by the visual adjustment of rod 56 in accordance with the disposition of calibration lines 57 relative to the outer edge of journal 54 or other suitable index, or by connecting control rod 56 to `an engine throttle or the like which may be mechanically, manually or pedally operated to produce predetermined settings or variations in the settings of camming surface 115 of cam 111. At each position of camming surface 115 of cam 111, each piston 101 is given an equal thrust by lthe action `of said cam to produce equal pressure conditions in cylinders S2, all of said pistons and cylinders having substantially identical dimensions. In some embodiments, the curvature of camming surface 115 may be shaped to provide for automatic advance fuel injection cooperating with corresponding automatic spark advance mechanisms as embodied in present automobiles. As the throttle action is increased through all degrees from minimum to full stroke, the angle of camming surface 115 increases relative to the inner ends of pistons 101 whereby the initial thrust produced upon said pistons is accelerated proportionately.

Depending upon the varying power requirements of the automotive engine, fuel injection piston 101 will be given varying pressure strokes by camming surface 115 of cam 111 in accordance with the positioning of control element 59. For low volume requirements, con- -tact between cammin-g surface 115 and the inner end of each piston 1011 will be comparatively short and takes place adjacent the rear end portion of said cammi-ng surface which is .terminated by a sharp angle in the profile of said cam (FIG. l2). With increasingly higher fuel requirements, for which cam 111 is adjusted pivotally, the time during which said camming surface 115 tis in contact with the end of each successive piston 101 increases proportionately during which proportionately longer pressure strokes are produced upon said pistons, and the length `of said contact extends forwardly from said rear terminal 6 of surface toward the pivot region of said cam. By this means, it is possible to ensure that substantially complete delivery of fuel from each pump cylinder 82 to a corresponding automotive engine cylinder will take place during the suction stroke of the corresponding engine piston.

I-n all conditions between minimum and maximum operative positions of cam 111, it is evident that the drop off of each pist-on at the rear end of camming surface 11'5 will `take place substantially at the same time during the radial traverse of shaft 35. rllhe operation of the fuel injection pump herein would obviously be timed in conjunction with the operation :of the engine pistons. Therefore, the eflciency of the fuel injection distributing pump herein is considerably greater than that obtainable with other mechanical fuel injection systems.

Control rod 56 may also be operatively connected by :suitable means to an actuator whose position is controlled by the .air pressure that exi-sts in the manifold of the internal combustion engine. Depending upon the fuel requirements in said manifold during the operation of the eng-ine, control rod 56 will be moved inwardly or outwardly to supply the requisite fuel through the fuel injection nozzles.

in some embodiments, control rod 56 is also connected to the throttle control of the engine for starting and idling purposes. After starting the engine, suitable dis* connect mechanisms may be provided to cause rod 56 to be controlled by manifold pressure alone.

Positioned within central chamber 46 in cylinder housing 21, and secured .therein by a press lit or the like, is a circular piston stop ring 117 having an L-shaped cross section (FIGS. 3 and 6), the annular ange 118 thereof extending axially a suflicient distance to form an abutment against which the inner ends of pistons 101 bear and which normally maintains said inner ends equ-idistant from the axial center of shaft 35. Thus, in this symmetrical circular array of pistons 101, the action of rocking cam 111, being set at any predetermined position, will produce an equal displacement for each piston in its pressure stroke within its respective cylinder 82. Pistons 101 are normally urged inward-ly into abutment with ange 118- by means that will be described hereinbelow.

in some embodiments, when rocking cam 111 is in the A position (FlG. l2), it is spaced apart from the inner ends of pistons 101 so that no fuel is being pumped by the apparatus as, for example, when the automobile is coasting, thereby realizing considerable economies in fuel consumption.

Although the inner ends of pist-ons 101 may be formed in any suitable shape, the embodiment in the drawings shows these inner ends as being shaped Iin the form of cones |122; while cam surface 115 of rocking cam 111 which makes cont-act with the piston is sloped laterally to match the angle of said cone. Since there is a continuing Iline contact between cam surface 115 and eachpiston cone 122 that is operative on one side of the apex of said cone, each piston 101 is rotated to some degree on its own longitudinal axis during each pressure stroke (FIGS. 3, 6). Thus a substantial rolling action rather than a complete Isliding action takes place between these two parts thereby reducing friction and wear.

By causing at yleast la partial rotation of each piston dur-ing each pressure stroke, any resulting wear due to -camming is distributed substantially uniformly over the surface of cone piston 122 while substantially even wear is produced on the respective contacting surfaces of cylinders 32 and pistons 101.

Furthermore, by matching the slopes of the inner ends of pistons 101 with the slope of cam surface 115, the contacting force is distributed over a fairly wide area, thereby preventing excessive wear in any particular region thereof. By virtue of the structures described herein, any wear that may be encountered is so evenly distributed over all of their contacting surfaces, that the pump maintains l its accuracy and efficiency substantially throughout its whole life, and produces a substantially uniform pumping action in all of its cylinders. Although the inner ends of pistons 101 are illustrated as being conical in shape, in some embodiments of the apparatus herein, the said inner ends may be rounded in contour.

The outer end of each cylinder 82 is provided with an outlet fitting which comprises a cylindrical plug 125 having a central aperture 126 aligned with the central axis of the cylinder. Near the inner end of said plug 125 is a peripheral annular recess 127 which accommodates a resilient O-ring 128, made of rubber or the like, to provide a liquid-tight seal between the plug and the interior wall of the cylinder.

A second peripheral annular recess 129 is provided in each plug 125 to serve as a keyway for the inner end of set screw 131 which maintains the distributor fitting fixed in position, after it has been rotated on its own axis in order to orient the direction of its transverse aperture 132 with which aperture 126 communicates. Connected to each aperture 132 is a distributor tube 133 which is adapted to be fitted to a fuel injection nozzle 134 (FIG. 3), which may be positioned in the manifold of an automotive engine or in the head of a corresponding engine cylinder.

Nozzle 134 has a combination structure which performs the functions of both a fuel injection spray device and a check valve. Each nozzle 134, which has a longitudinal central aperture 135, is connected at one end with a liquid tight seal to the end of a corresponding tube 133. Aperture 135, which communicates with the bore of tube 133, terminates some distance short of the other end of nozzle 134 and is intersected by a transverse bore 136, the outer ends of which open into an annular V-groove 137.

Although bore 136 is formed virtually of two radial bores positioned 180 apart, it is contemplated that in some embodiments only one radial bore will be provided while in other embodiments more than two spaced apart radial bores rnay be desired or effective.

A resilient O-ring 138, made of rubber or the like, is nested tightly within groove 137 and has sufficient tension normally to seal said V-groove against the escape of any liquid between the walls of said O-ring and said V-groove. The tension of O-ring 13S is arranged to exert a predetermined resistance to pressure of fluid passing through aperture 135 and emerging from bore 136. The tension rating of said O-ring is generally set at somewhat higher level than the hydraulic pressure that exists as a base pressure in respective cylinders 82 of the distributor pump.

By virtue of the tension exerted yby O-ring 138, liquid in each cylinder 82 will be contained therein up to a predetermined threshold pressure. An increase of pressure above that threshold pressure produced by the pressure stroke of a piston 101 in its respective cylinder 82, will cause the expansion of O-ring 138 to permit fluid from bore 136 to ow outwardly between the walls of V- groove 137 and the periphery of O-ring 138. Sufficient tension remains in O-ring 138 to cause the flow of liquid to be transformed into a fine spray whereby the fuel becomes intimately mixed with the air as it is drawn into a respective cylinder to the internal combustion engine.

The peripheral edge 139 of the rearward wall of V- groove 137 may be formed into an acute angle whereby liquid fuel emerging from between said wall and the O-ring will not collect at said edge and form droplets of fuel which might diminish the efiicacy of the fuel injection nozzle 134.

Liquid or fuel is supplied to the distributor pump from a supply tank 145 by way of feed or supply tube 146, one end of which extends into the liquid 147 in said tank, and the other end of which is connected by a liquid tight seal to inlet 73, as shown schematically in FIG. 3. Connected in the line of tube `146 is a pump 148 which is operative to provide and maintain a continuing fundamental base liquid pressure in the system constituted by inlet apertures 71, inlet groove 74, cylinders 82, distributor tubes 133, and bores and 136 in nozzle 134. Pump 148 is operated by electric motor 149 or other suitable motive means.

The fundamental base pressure maintained by pump 148 serves to urge all the freely movable pistons 101 inwardly whereby their inner ends normally rest against ange 118 of stop ring 117. After pistons 101 have been actuated sucessively as described hereinabove, to produce their respective pressure strokes, and after they have been released by cam 111, they are returned promptly to their retracted positions by the fundamental base pressure maintained by pump 146 operating through the unidirectional valves in inlet valve apertures 81, while at the same time the respective cylinders 82 are completely refilled with fuel.

Furthermore, by keeping all of the cylinders 82 and their individually associated liquid systems completely filled with liquid, the system is primed and ready at all times to supply fuel injection sprays to the respective internal combustion engine cylinders instantaneously upon the actuation of pistons 101 to produce pressure strokes in their respective cylinders.

Referring to FIG. 13, there is shown an alternative means for returning each piston 101 to its retracted position. This comprises a coiled spring 150, one end of which is seated in the annular groove of U-cup 103, the other end of which is urged against the inner end of plug 125. If the fuel supply pressure is inadequate for any reason, spring 150 ensures the return of the piston 101 to its innermost retracted position after its pressure stroke is completed. Additionally, in some embodiments, spring 150 can produce a return suction stroke on the part of the piston to fill its respective cylinder with fuel after the piston has been released by cam 111.

FIG. l5 shows an alternative to the unidirectional inlet valve assembly shown in FIGS. 7 and 9. This is in the form of a cylindrical valve body 153 positioned in aperture 81, and having a peripheral annular recess 154 which accommodates a resilient O-ring 155, made of rubber or the like, said 0-ring providing a liquid-tight seal between the outer surface of said body and the interior surface of said aperture.

Near the inner head portion of valve body 153 is a peripheral annular V-shaped groove 156 which accommodates a resilient O-ring 157 made of rubber or the like, which is nested under tension within said groove, its outer surfaces being spaced apart from the interior walls of aperture 81.

Valve body 153 has a longitudinal central bore 15S that terminates just short of the inner end of said body. Bore 158 has a widened circular mouth 159 which overlaps inlet groove 74 in housing 24 whereby liquid may flow through body 153. Central bore 158 is intersected by one or more radial bores 161 opening into V-groove 156.

Fluid passing from inlet groove 74 of inlet housing 24 through central `bore 158, and outwardly through intersecting bores 161 at a suitable predetermined pressure causes the dilation of O-ring 157, to permit the fluid to bypass said O-ring and ow around the narrowed inner end of body 153, through port 95 and thence to its respective cylinder 82.

When each cylinder 82 associated with a particular inlet valve becomes filled with liquid by the operation of pump 148, the pressure in said cylinder becomes approximately equal to the inlet pressure in inlet groove 74 at which time `C-ring 157 is caused to seat itself within V- groove 156 due to the inherent tension of said O-ring. Under each pressure stroke of each piston 101 in its respective cylinder 32, the liquid pressure therein rises thereby producing an external pressure upon O-ring 157 causing the latter to wedge more tightly into its groove to prevent liquid from flowing back through valve 153. The central bore 15S of each valve body 153 may be threaded in order to accommodate a threaded tool whereby said body may be inserted into and removed from its respective inlet aperture 31.

Although the apparatus illustrated and described herein exemplifies a system for use with an eight cylinder internal combustion engine, it is understood that the apparatus may readily be adapted for use with engines having different numbers of cylinders.

As shaft 35 rotates, and control rod 55 is manipulated to operate cam 111, cam surface 115 thereof impinges repeatedly in succession upon the inner ends of pistons 101 to cause the latter to produce discharge strokes for urging fuel through the respective injection nozzles 134 positioned lat or near the fuel intake valves of the respective cylinders of the engine. A substantially constant head of fuel supply pressure is maintained by pump 148 whereby the free pistons 101 are caused to return to their original position-s against ring 117, yafter they have produced their respective discharge strokes.

The unidirectional valves positioned between conduits 74 and each of the respective cylinders 82 insure that fuel from each of said cylinders under the action of the discharge strokes of pistons lill will emerge only from the respective injection nozzles 134. By manipulating control rod 56 inwardly and outwardly through journal 54, the length of the piston strokes are varied, and accordingly, the volume of fuel transmitted through the respective nozzles 134 is also varied in order to produce varying speeds or power of operation of the engine.

In the specification, there is explained the principles of the invention, and the best mode in which it is contemplated applying those principles, so a-s to distinguish the invention tfrom other inventions; 4and I have particularly pointed out and distinctly claimed the part, mode or combination which I claim as my invention or discovery.

While I have shown and described certain preferred embodiments of my invention, it will be understood that modifications and changes may be made without departing from the function and scope thereof, 'as will be clear to those skilled in the art.

It is claimed l. A pump comprising a pump body, a plurality of cylinders radially arrayed in said body, a rotatable drive shaft mounted in said body and positioned centrally of said array of cylinders, a piston in each of said cylinders movable freely longitudinally therein, said pistons normally resting at the inner ends of their respective cylinders, a cam mounted pivotably on said shaft, a portion of said cam successively engaging the inner ends of each of said pistons as said shaft rotates to cause said pistons to produce outward pressure strokes within their respective cylinders, an axial aperture in saidz shaft, a cam control element capable of rectilinear movement in said aperture, a radial bore in said shaft communicating with said axial aperture, a plunger movable longitudinally in said bore, the outer end of said plunger being adapted to cause the pivotal movement of said cam, a sloping camming surface on said cam control element, the inner end of said plunger bearing `against said cam-ming surface, the movement of said cam control element causing said plunger to control the position of said cam whereby a pressure stroke of the desired magnitude is produced by each of said pistons when engaged by said cam, and an elongated extension on said cam, said extension being operative when said shaft rotates to move outwardly under centrifugal force and to cause the cam to bear against the outer end of said plunger and to cause the inner end of said plunger to bear continuously against said cam control element.

2. A pump according to claim l, and further comprising a bushing mounted on said body, a central aperture in said bushing positioned coaxially relative to the central aperture of said shaft, a portion of said cam control element being movable longitudinally only within the central aperture of said bushing, a control rod movable longitudinally within the aperture of said bushing, said cam control element being connected to said control rod, the connection between said control rod and said cam control element permitting the rotation of said control element on its longitudinal axis, a'longitudinal keyway on said cam control element, a pin in said shaft adapted to cooperate with said keyway whereby the rotation of said shaft causes the rotation of said cam control element irrespective of the longitudinal position of said cam control element in relation to sai-d shaft.

3. A liquid distributing device comprising a pump lbody, a plurality of cylinders radially arrayed in said body, a rotatable drive shaft mounted in said body and positioned coaxially within said array of cylinders, a piston in each of said cylinders, `a cam freely pivotably mounted on said shaft, 'a portion of said cam successively engaging the inner ends of each of said pistons as said shaft rotates to cause said pistons to produce outward pressure strokes within their respective cylinders, `an axial aperture in said shaft, a control element movable rectilinearly in said aperture, a radial bore in said shaft communicating with said axial aperture, a plunger movable longitudinally in said bore, the outer end of said plunger determining the position of said cam, a sloping camming surface on said control element, the inner end off said plunger bearing against said camming surface, the selected position of said control element determining the position of said plunger which, in turn, determines the position of said cam whereby a pressure stroke of the desired magnitude is produced -by each of said pistons when engaged by said cam, and an extension on said cam, said extension being operative when said shaft rotates to move outwardly under centrifugal force and to cause the cam to bear against the outer end of said plunger.

4. A pump comprising a pump body, a plurality of cylinders radially arrayed in said body, a plurality of unidirectional inlet Avalves in said body, each of said valves being `arranged to supply liquid to a corresponding cylinder, a separate outlet port for each of said cylinders, a piston in each of said cylinders movable freely therein, an aperture in said pump body located centrally of said array of cylinders, -a drive shaft rotatably positioned in said aperture, a cam pivotally mounted on said drive shaft, a camming surface on said cam adapted to engage the inner ends of said pistons in succession as said shaft rotates and to urge said pistons outwardly to produce pressure strokes in their respective cylinders, means for normally causing said pistons to move inwardly toward said drive shaft after being actuated by said cam, means on said shaft for Pivo-tally adiusting said cam in a predetermined location in respect of its pivot mounting to produce a corresponding desired length of pressure stroke for each of said pistons, the positioning of said cam in different operating locations providing differing times of contact between said camming surface and the inner ends of each of said pistons.

5. A pump according to claim 4 wherein said camming surface terminates sharply at the rear end of said cam and permits the rapid return movement of said pistons, and wherein the operative action of said cam takes place on a length of the camming sur-face from said termination point for a distance proportional to the length of the pressure stroke produced upon said pistons by said cam.

6. A pump according to claim 4 wherein said cam comprises a forwardly extending integral element on one side of the pivot mounting of said cam, and a rearwardly extending integral element on the other side of said pivot mounting, a surface of said rearward element comprising the camming surface of said cam, the forwardly extending element producing a centrifugal action upon said cam when said shaft rotates to maintain said cam in operational relationship to the pivoting means on said shaft.

7. A pump comprising a pump body, a plurality of cylinders radially arrayed in said body, a rotatable drive shaft mounted in said body and positioned centrally of said array o-f cylinders, a piston in each of said cylinders movable freely longitudinally therein, a cam `freely pivotably mounted on said shaft and acting directly upon the inner ends of each of said pistons successively as said shaft rotates, an axial aperture in said shaft, a cam control element positioned Within said aperture and adapted to cooperate with said cam on one side of said pivot mounting, said cam control element rotating with said shaft and also being movable longitudinally therein, the longitudinal adjustment of said cam control element being operative to change the position of said cam in order to control the extent to which said cam causes the outward movement of said pistons, an extension on said cam on the other side of said pivot mounting, said extension being operative when said shaft rotates to move outwardly under centrifugal force and to cause said cam to be urged into cooperative contact with said cam control element.

8. A pump comprising a pump body, a plurality of cylinders radially arrayed in said body, a plurality of unidirectional inlet valves in said body, each of said valves being arranged to supply liquid to a corresponding cylinder, a separate outlet port for each of said cylinders, a piston in each of said cylinders movable freely therein, an aperture in said pump body located centrally of said array of cylinders, a drive shaft rotatably positioned in said aperture, a single cam pivotaily mounted on said drive shaft, a first portion of said cam on one side of the pivot mounting acting directly upon said pistons to urge the latter outwardly in their respective cylinders individually and in succession as said `shaft rotates, another portion of said cam on the other side of said pivot mounting and having suliicient mass to operate solely by centrifugal force as said shaft rotates normally to cause the first portion of said cam to be retracted from said pistons, a cam control element movable on said shaft and adapted to operate directly upon the rist mentioned portion of said cam to cause the Ilatter to assume a predetermined position in its operation on said pistons to cause the latter to produce pressure strokes of predetermined magnitude within their respective cylinders.

9. A pump according to claim 8 wherein said pistons are movable to a base location in their respective cylinders from which they produce their respective pressure strokes, and further comprising an inlet port in said body communicating with each of said valves, a liquid supply source connected to said inlet port, a vsupply pump connected between said supply source and said inlet port for producing sufiicient liquid pressure through all of said valves whereby said pressure in said cylinders normally causes their respective pistons to return to base positions after they have produced their respective pressure strokes.

10. A pump comprising a pump body, a plurality of cylinders radially arrayed in said body, a rotatable drive shaft mounted in said body and positioned centrally of said array of cylinders, a piston in each of said cylinders movable freely longitudinally therein, a cam pivotably mounted on said shaft and acting directly upon the inner ends of each of said pistons successively as said shaft rotates, an axial aperture in said shaft, a radial aperture in said shaft communicating with said axial aperture, a plunger movable longitudinally in said radial aperture, a cam control element positioned within said axial aperture, said cam control element rotating with said shaft and also being movable longitudinally therein, a sloping cam surface on said cam control element, the inner end of said plunger being engaged by said sloping surface, the outer end of said plunger engaging said cam, the longitudinal movement of said cam control element being operative to move said plunger, which in turn is operative to pivotally alter the position of said cam in order to control the extent to which `said cam causes the outward movement of said pistons.

11. A pump according to claim l0, and further comprising an extension of said pivoting cam, said extension being operative when said shaft rotates to move outwardly under centrifugal force and to cause said pivoting cam to be urged into cooperative contact with said plunger and to urge the inner end of the latter against said sloping cam surface.

12. A liquid distributing apparatus, comprising a pump body, a plurality of cylinders radially arrayed in said body, a rotatable drive shaft mounted in said body and positioned coaxially within said array of cylinders, a piston in each of said cylinders, rst freely pivoting means on said shaft successively engaging the inner ends 4of each of said pistons as said shaft rotates to cause said pistons to provide outward pressure strokes within their respective cylinders, second means movable rectilinearly along said shaft, third means on said shaft movable laterally relative thereto, said third means being movable by the movement of said second means, fourth means integral with said first means and operable under the action of centrifugal force as said shaft rotates to maintain said first means continuously in contact with said third means and said third means continuously in contact with said second means, said third means being operative upon said rst means to determine the position of the latter according as said second means is positioned whereby a pressure stroke of the desired magnitude is produced by each of said pistons when engaged by said rst means.

13. A liquid distributing apparatus comprising a pump body, a rotatable drive shaft mounted in said body, a plurality of cylinders in said body, said cylinders being arrayed around said drive shaft, a piston in each of said cylinders, first freely pivoting means on said shaft successively engaging the inner ends of each of said pistons las said shaft rotates to cause said pistons to provide pressure strokes within their respective cylinders, second means movable -rectilinearly along said shaft, third means on said shaft movable laterally thereto, said third means being movable by the movement of said second means, said third means being operative upon said first means to determine the position of the latter according as said second means is positioned whereby the pressure stroke of the desired magnitude is produced by each of said pistons when engaged by said rst means, and fourth means connected to said first means and operable by centrifugal force only :as said shaft rotates to maintain said first means continually in contact with said third means whereby the latter is caused continuously to maintain contact with said second means.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PUMP COMPRISING A PUMP BODY, A PLURALITY OF CYLINDERS RADIALLY ARRAYED IN SAID BODY, A ROTATABLE DRIVE SHAFT MOUNTED IN SAID BODY AND POSITIONED CENTRALLY OF SAID ARRAY OF CYLINDERS, A PISTON IN EACH OF SAID CYLINDERS MOVABLE FREELY LONGITUDINALLY THEREIN, SAID PISTONS NORMALLY RESTING AT THE INNER ENDS OF THEIR RESPECTIVE CYLINDERS, A CAM MOUNTED PIVOTABLY ON SAID SHAFT, A PORTION OF SAID CAM SUCCESSIVELY ENGAGING THE INNER ENDS OF EACH OF SAID PISTONS AS SAID SHAFT ROTATES TO CAUSE SAID PISTONS TO PRODUCE OUTWARD PRESSURE STROKES WITHIN THEIR RESPECTIVE CYLINDERS, AN AXIAL APERTURE IN SAID SHAFT, A CAM CONTROL ELEMENT CAPABLE OF RECTILINEAR MOVEMENT IN SAID APERTURE, A RADIAL BORE IN SAID SHAFT COMMUNICATING WITH SAID AXIAL APERTURE, A PLUNGER MOVABLE LONGITUDINALLY IN SAID BORE, THE OUTER END OF SAID PLUNGER BEING ADAPTED TO CAUSE THE PIVOTAL MOVEMENT OF SAID CAM, A SLOPING CAMMING SURFACE ON SAID CAM CONTROL ELEMENT, THE INNER END OF SAID PLUNGER BEARING AGAINST SAID CAMMING SURFACE, THE MOVEMEMT OF SAID CAM CONTROL ELEMENT CAUSING SAID PLUNGER TO CONTROL THE POSITION OF SAID CAM WHEREBY A PRESSURE STROKE OF THE DESIRED MAGNITUDE IS PRODUCED BY EACH OF SAID PISTONS WHEN ENGAGED BY SAID CAM, AND AN ELONGATED EXTENSION ON SAID CAM, SAID EXTENSION BEING OPERATIVE WHEN SAID SHAFT ROTATES TO MOVE OUTWARDLY UNDER CENTRIFUGAL FORCE AND TO CAUSE THE CAM TO BEAR AGAINST THE OUTER END OF SAID PLUNGER AND TO CAUSE THE INNER END OF SAID PLUNGER TO BEAR CONTINUOUSLY AGAINST THE SAID CAM CONTROL ELEMENT. 